THEY’VE toured with U2, Take That and Paul McCartney. Their current arena tour sold out in days, with more dates added to meet demand in key cities.

The Script are at their best live, and they like nothing better than playing in Liverpool.

“We’ve played in Liverpool loads of times before, and each time we’ve had a great gig,” says singer Danny O’Donoghue. “I love Liverpool. They say Liverpool is the capital of Dublin. They’re not far off. The people are so similar.”

Danny and guitarist Mark Sheehan met in their teens in the James Street area of Dublin, near the Guinness brewery, gravitating to each other through a shared obsession with music.

They have gone on to become one of the biggest bands in the world.

In four years, the trio have sold 4m albums and 10m singles, amassed almost 4m followers on Facebook, 1.5m on Twitter, wracked up 100m YouTube views, and saw their singer star on TV talent show, The Voice.

Barely back from 18 months on the road, Danny became a coach on the BBC show just as work on their latest album began.

He spent long days in a TV studio, then up to 12 hours a night in a recording studio with the band.

“I feel more at home here, in a padded room, than anywhere else in the world right now,” says Danny.

“For six months, it was my home. will.i.am used to say that, every day, I came in with another song idea or singing new lyrics.

“I had to because I was laying them down that night.”

In Danny’s absence, Mark and drummer Glen Power picked up his production slack in order to stay on schedule.

“It was a band decision for Danny to do The Voice,” insists Mark.

“We don’t want to be celebrities. We can’t stand that scene. We spent two albums avoiding the limelight, letting our music do all the talking. But because of that we were, to some extent, a faceless band.

“Danny did The Voice to put a face to The Script. We know about producing, song writing and performing – we’ve been doing it since we were 14 or 15.

Danny on a show about singing was good for us. People saw how passionate he is about music, how much it means to him and it made our band better known.”

The album #3 – featuring vocals from American rapper and singer-songwriter will.i.am – became the band's first UK singles chart number one single in September last year. The song was written in just a day.

“We played half a dozen demos to Will and he wanted Hall Of Fame for his record,” recalls Danny.

“He was going overboard about it – saying it was the new We Are The World, how he'd take it and get loads of people to sing on it. But we thought it would make a great duet. Not the usual, 'Get a rapper, have him come in on the middle eight' stuff. We wanted to do it line by line, true duet style. It took several months, a headlock and a taxi cab to pin Will down. He kept saying he’d come in to the studio that night, but something else always came up.

“One night after The Voice, as he was heading back to his hotel, I told him I was coming with him. I jumped in to his car, called Mark and said 'S***, we’re doing it now. Get in a taxi'. We were trying to play it super cool – us with will.i.am! We heard him singing some of our lines, but we still didn’t know what he was going to do. We were worried he might take some of our original song out. But he just sang our words.

“When he finished, I put the tape in my bag and we left his hotel room, trying to act like it was no big deal. But soon as we shut the door, Mark and I were punching the air, shouting yes! We felt like we'd just robbed will.i.am. A smash and grab with the loot in my bag! Then it was straight to the bar to celebrate.”

There’s a recurring theme in the album’s title. There are the three of them. It was written and recorded in studio three at Battersea’s Sphere Studios.

“There’s a synergy to three,” says singer Danny. “If you delve in to it – which we tend to do with everything – it’s a lucky number, in the past a religious number. But the title is mostly about us. As any geek fan of the band could tell you, we’re all extremely different people, but magic happens when you mix us together. Well, magic or a car crash, which is how we describe the songs we scrap.”

There are some close to the bone songs on the album. If You Could See Me Now addresses the death of Mark’s parents and of Danny’s father, with alternative verses delivered by both singers. It was written over bottles of whisky and through rivers of tears.

“As writers, we’re used to venting everything in song,” says Mark. “But that was the one topic for two albums we always shied away from. One night, I’d brought in a number of whiskies I wanted the guys to try – that was the porthole. We had to be drunk to tackle that song. Danny and I sat in opposite corners of the studio, writing our verses.

“I’ll remember that night for the rest of my life,” says Danny.

“Emotionally, we achieved exactly what we got in to music for, what we’re all still in it for. Not the No1 singles or the fame, but to capture an emotion in 3½ minutes that we know will mean an awful lot to other people.

“As a band, writing that song was the bravest thing we’ve ever done. It’s us imagining what our parents would say were they still here.

“We like to think they would be proud of us and our achievements, but they’d probably be telling us off for drinking and smoking and swearing too much. And you know what, they’d be right.”